Simulators are used extensively by the military to train fighter pilots. It is important that a simulator provide as realistic an experience as possible. A fighter jet simulator concurrently simulates many aspects of a flight, such as an out-the-window (OTW) simulation simulating what a pilot sees out the cockpit window while flying the fighter jet, and a radar simulation simulating what a pilot sees when looking at a radar display.
Some current generation fighter jets include a synthetic aperture radar (SAR) which provides a pilot with a high-resolution SAR map of potential targets on the ground. SAR is typically simulated using a Digital Radar Landmass Simulator (DRLMS). A SAR map includes terrain, lineal features such as roads and railroad tracks, and three-dimensional (3D) content of elevated features, including natural and cultural features such as buildings, vegetation canopy, and the like. 3D content in a SAR map is particularly important because of the importance of radar shadows for feature and object identification by a pilot or image analyst. Conventional mechanisms for injecting primary 3D content, such as buildings and trees, into a radar map include the generation of 3D polygonal models. Unfortunately, 3D polygonal development of high density urban areas is time intensive and costly. Moreover, because of the cost associated with manual 3D polygonal development, many of the ancillary features, such as cars, rocks, and bushes, are simulated using available ground imagery. While ground imagery may be acceptable for lower resolution radar simulations, in a high-fidelity SAR map simulation such ancillary features will appear flat, rendering the simulation unrealistic.
A DRLMS includes a database compiler, sometimes referred to as a formatter, which receives data defining attributes of the SAR scenery, and integrates and rasterizes the data to generate a proprietary runtime database of the SAR map. The data may be received from multiple files, each of which may be in a different format. For example, some of the data may be in a raster format, and other data may be in a vector format. Integrating such data and rasterizing vector-based data requires significant processing power and may take a substantial amount of time. Moreover, the use of different formats and different input sources makes it difficult to ensure quality control of the final runtime database. Finally, each DRLMS vendor uses a database compiler that requires data to be in a particular format, requiring different sets of data for the same SAR map simulation when using different DRLMSs. Accordingly, there is a need for a raster-based interchange file format (IFF) suitable for defining all aspects of SAR scenery that may be used by any DRLMS database compiler that is written to understand the IFF. There is also a need for a mechanism for defining 3D content in a SAR map without having to model each 3D feature using polygonal modeling techniques.